1. Field of the Invention
The present invention relates to a substrate processing method and a substrate processing apparatus for efficiently removing a resist film from a substrate having the resist film formed thereon, and a computer program, and a computer readable storage medium.
2. Description of the Related Art
In the manufacturing process of a semiconductor device, a circuit pattern is formed by mainly a so-called “photolithography process”. The photolithography process includes, for example, the steps of forming a metal film on the surface of a semiconductor wafer by the PVD process or a CVD process, forming a resist film on the metal film, exposing the resist film to light in a prescribed pattern, followed by developing the light-exposed pattern formed in the resist film to form a circuit pattern made of the resist film, selectively etching the metal film with the resist film used as an etching mask to form a metal wiring pattern, and removing the resist film after formation of the metal wiring pattern.
Also, a so-called “damascene process” is widely employed for the manufacture of a semiconductor device comprising a multi-layered wiring. A single damascene process includes, for example, the steps of forming an interlayer insulating film on a substrate having a metal wiring formed thereon, forming a resist film on the interlayer insulating film, selectively exposing the resist film to light in a prescribed pattern, followed by developing the light-exposed resist film to form a circuit pattern made of the resist film, applying a plasma etching to the semiconductor wafer with the patterned resist film used as an etching mask to form vias and trenches in the interlayer insulating film, and removing the resist film after formation of the vias and the trenches.
A plasma ashing method is widely employed in the circuit-forming process described above as a method of removing the resist film from the semiconductor wafer having the resist film, which is adapted for, for example, the KrF line, formed thereon. In the plasma ashing method, however, a damage tends to be done to the underlying metal film. Also, the insulating film is likely to be excessively removed.
Such being the situation, Japanese Patent Disclosure (Kokai) No. 2002-184741 discloses a method that permits avoiding the difficulties pointed out above. To be more specific, disclosed in this prior art is a substrate processing method comprising the steps of processing the substrate with a gas containing ozone and a water vapor so as to denature the resist film such that the resist film is made soluble in water, and processing the substrate with a pure water so as to remove the denatured resist film from the semiconductor wafer.
However, the processing method disclosed in Japanese Patent Disclosure No. 2002-184741 quoted above is defective in that the peeling rate is low, compared with the plasma ashing process, with the result that a long processing time is required. It should be noted in this connection that a practical use of an ArF excimer laser as an exposure light source is being promoted in an attempt to make finer the circuit pattern. What should be noted is that the method disclosed in the patent document quoted above is incapable of peeling off the resist film adapted for the ArF line and the antireflection film that is used together with the resist film. Under the circumstances, it is unavoidable nowadays to employ the plasma ashing process that tends to do damage to the underlying layer.